Abrupt transition in quasiparticle dynamics at optimal doping in a cuprate superconductor system

We report time-resolved measurements of the photoinduced change in reflectivity, Delta R, in the Bi2Sr2Ca(1-y)Dy(y)Cu2O(8+delta) (BSCCO) system of cuprate superconductors as a function of hole concentration. We find that the kinetics of quasiparticle decay and the sign of Delta R both change abruptly where the superconducting transition temperature Tc is maximal. These coincident changes suggest that a sharp transition in quasiparticle dynamics takes place precisely at optimal doping in the BSCCO system.Comment: 10 pages, 4 figure

Modeling Ferro- and Antiferromagnetic Interactions in Metal-Organic Coordination Networks

Magnetization curves of two rectangular metal-organic coordination networks formed by the organic ligand TCNQ (7,7,8,8-tetracyanoquinodimethane) and two different (Mn and Ni) 3d transition metal atoms [M(3d)] show marked differences that are explained using first principles density functional theory and model calculations. We find that the existence of a weakly dispersive hybrid band with M(3d) and TCNQ character crossing the Fermi level is determinant for the appearance of ferromagnetic coupling between metal centers, as it is the case of the metallic system Ni-TCNQ but not of the insulating system Mn-TCNQ. The spin magnetic moment localized at the Ni atoms induces a significant spin polarization in the organic molecule; the corresponding spin density being delocalized along the whole system. The exchange interaction between localized spins at Ni centers and the itinerant spin density is ferromagnetic. Based on two different model Hamiltonians, we estimate the strength of exchange couplings between magnetic atoms for both Ni- and Mn-TCNQ networks that results in weak ferromagnetic and very weak antiferromagnetic correlations for Ni- and Mn-TCNQ networks, respectively.Comment: 27 pages, 6 figures, accepted for publication; Journal of Physical Chemistry C (2014

CacheZoom: How SGX Amplifies The Power of Cache Attacks

In modern computing environments, hardware resources are commonly shared, and parallel computation is widely used. Parallel tasks can cause privacy and security problems if proper isolation is not enforced. Intel proposed SGX to create a trusted execution environment within the processor. SGX relies on the hardware, and claims runtime protection even if the OS and other software components are malicious. However, SGX disregards side-channel attacks. We introduce a powerful cache side-channel attack that provides system adversaries a high resolution channel. Our attack tool named CacheZoom is able to virtually track all memory accesses of SGX enclaves with high spatial and temporal precision. As proof of concept, we demonstrate AES key recovery attacks on commonly used implementations including those that were believed to be resistant in previous scenarios. Our results show that SGX cannot protect critical data sensitive computations, and efficient AES key recovery is possible in a practical environment. In contrast to previous works which require hundreds of measurements, this is the first cache side-channel attack on a real system that can recover AES keys with a minimal number of measurements. We can successfully recover AES keys from T-Table based implementations with as few as ten measurements.Comment: Accepted at Conference on Cryptographic Hardware and Embedded Systems (CHES '17

Stealthy Deception Attacks Against SCADA Systems

SCADA protocols for Industrial Control Systems (ICS) are vulnerable to network attacks such as session hijacking. Hence, research focuses on network anomaly detection based on meta--data (message sizes, timing, command sequence), or on the state values of the physical process. In this work we present a class of semantic network-based attacks against SCADA systems that are undetectable by the above mentioned anomaly detection. After hijacking the communication channels between the Human Machine Interface (HMI) and Programmable Logic Controllers (PLCs), our attacks cause the HMI to present a fake view of the industrial process, deceiving the human operator into taking manual actions. Our most advanced attack also manipulates the messages generated by the operator's actions, reversing their semantic meaning while causing the HMI to present a view that is consistent with the attempted human actions. The attacks are totaly stealthy because the message sizes and timing, the command sequences, and the data values of the ICS's state all remain legitimate. We implemented and tested several attack scenarios in the test lab of our local electric company, against a real HMI and real PLCs, separated by a commercial-grade firewall. We developed a real-time security assessment tool, that can simultaneously manipulate the communication to multiple PLCs and cause the HMI to display a coherent system--wide fake view. Our tool is configured with message-manipulating rules written in an ICS Attack Markup Language (IAML) we designed, which may be of independent interest. Our semantic attacks all successfully fooled the operator and brought the system to states of blackout and possible equipment damage

Management of cancer-associated anemia with erythropoiesis-stimulating agents: ASCO/ASH clinical practice guideline update.

PURPOSE: To update the American Society of Clinical Oncology (ASCO)/American Society of Hematology (ASH) recommendations for use of erythropoiesis-stimulating agents (ESAs) in patients with cancer. METHODS: PubMed and the Cochrane Library were searched for randomized controlled trials (RCTs) and meta-analyses of RCTs in patients with cancer published from January 31, 2010, through May 14, 2018. For biosimilar ESAs, the literature search was expanded to include meta-analyses and RCTs in patients with cancer or chronic kidney disease and cohort studies in patients with cancer due to limited RCT evidence in the cancer setting. ASCO and ASH convened an Expert Panel to review the evidence and revise previous recommendations as needed. RESULTS: The primary literature review included 15 meta-analyses of RCTs and two RCTs. A growing body of evidence suggests that adding iron to treatment with an ESA may improve hematopoietic response and reduce the likelihood of RBC transfusion. The biosimilar literature review suggested that biosimilars of epoetin alfa have similar efficacy and safety to reference products, although evidence in cancer remains limited. RECOMMENDATIONS: ESAs (including biosimilars) may be offered to patients with chemotherapy-associated anemia whose cancer treatment is not curative in intent and whose hemoglobin has declined to \u3c 10 g/dL. RBC transfusion is also an option. With the exception of selected patients with myelodysplastic syndromes, ESAs should not be offered to most patients with nonchemotherapy-associated anemia. During ESA treatment, hemoglobin may be increased to the lowest concentration needed to avoid transfusions. Iron replacement may be used to improve hemoglobin response and reduce RBC transfusions for patients receiving ESA with or without iron deficiency. Additional information is available at www.asco.org/supportive-care-guidelines and www.hematology.org/guidelines

Nonlinear Dynamics of the Perceived Pitch of Complex Sounds

We apply results from nonlinear dynamics to an old problem in acoustical physics: the mechanism of the perception of the pitch of sounds, especially the sounds known as complex tones that are important for music and speech intelligibility

Ferromagnetic Enhancement of CE-type Spin Ordering in (Pr,Ca)MnO3_3

We present resonant soft X-ray scattering (RSXS) results from small band width manganites (Pr,Ca)MnO$_3$, which show that the CE-type spin ordering (SO) at the phase boundary is stabilized only below the canted antiferromagnetic transition temperature and enhanced by ferromagnetism in the macroscopically insulating state (FM-I). Our results reveal the fragility of the CE-type ordering that underpins the colossal magnetoresistance (CMR) effect in this system, as well as an unexpected cooperative interplay between FM-I and CE-type SO which is in contrast to the competitive interplay between the ferromagnetic metallic (FM-M) state and CE-type ordering.Comment: Accepted for publication in Phys. Rev. Let

The FiDel model at 7 TeV

After the long shut down of 2013-2014, the LHC energy will be pushed toward 7 TeV. In this range of energy, the main magnets will enter a new regime. For this reason, this paper will present a detailed study of the performance of the FiDeL model that could be critical for the operation in 2015. In particular this paper will study the saturation component and its precision in the model, the errors due to the hysteresis, and an estimate of the dynamic effects for the 7 TeV operation.peer-reviewe